ARS | Publication request: Bioassay of estrogenicity and chemical analysis of estrogens in streams across the United States associated with livestock operations

Submitted to: Water Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 13, 2013
Publication Date: June 15, 2013
Citation: Alvarez, D.A., Shappell, N.W., Billey, L.O., Bermudez, D.S., Wilson, V.S., Kolpin, D.W., Perkins, S.D., Evans, N., Foreman, W.T., Gray, J.L., Shipitalo, M.J., Meyer, M.T. 2013. Bioassay of estrogenicity and chemical analysis of estrogens in streams across the United States associated with livestock operations. Water Research. 47:3347-3363.

Interpretive Summary: Animal manures are often applied to croplands as a fertilizer even if the croplands are adjacent to streams. Potent estrogenic compounds including estradiol are present in animal manures and it is possible that these estrogens could find their way to surface waters and streams through normal water movement and through rain events. The objective of this study was to measure estrogens and estrogenic activity in streams associated with livestock production systems; an additional goal was to compare methods of measuring estrogenic activity on "real world" samples. To this end, numerous water samples were taken from 19 small watersheds, and estrogen and estrogenic activity were measured in the samples. Regardless of the watershed, estrogenic activity was always below the level (10 ng/L) considered to have potential negative impacts on fish. From a technical point of view, the type of analytical method used to assess estrogenic activity should be selected based on the need. For example, the T47D-KBluc bioassay should be used if the goal is to detect any estrogenic activity, even if the activity is from estrone, an estrogen metabolite of fairly low environmental concern. If only relatively high levels of estrogenic activity are of concern, the YES bioassay may be adequate.

Technical Abstract: Animal manures, used as a nitrogen source for crop production, are often associated with negative impacts on nutrient levels in surface water. The concentration of estrogens in streams from these wastes is of concern due to potential endocrine disruption in aquatic species. Streams associated with livestock operations were sampled by grab sample or by time-integrated polar organic chemical integrative samplers (POCIS). Samples were analyzed for estrogens by gas chromatography-tandem mass spectrometry (GC-MS2) and estrogenic activity was assessed by three bioassays. Samples were collected from 19 streams within small (~1 to 30 km2), watersheds in 12 US states representing a range of hydrogeologic conditions, dominated by: dairy (3); grazing (3) and confined beef cattle (1); swine (5); poultry (3); and 4 areas where no livestock were raised or manure applied. Discrete (n = 38) and POCIS (n = 19) samples from each watershed were analyzed using Yeast Estrogen Screen (YES), T47D-KBluc Assay, MCF7 Estrogenicity Screen (E-Screen) and GC-MS2. Water samples were consistently below the proposed Lowest Observable Effect Concentration for estradiol in fish (10 ng/L) in all watersheds, regardless of land use. Estrogenic activity was often higher in samples during runoff conditions following a period of manure application. Estrone was the most commonly detected estrogen (13 of 38 water samples, mean 1.9, max 8.3 ng/L. Because of the T47D-KBluc assay’s sensitivity towards estrone (1.4 times estradiol) it was the most sensitive method for detecting estrogens, followed by the E-Screen, GC-MS2, and YES. POCIS resulted in greater detection of estrogens than discrete water samples across all sites, even with the less sensitive YES bioassay.